English Abstract

The Property of Buildings with Seismic Isolation Systems in the 2011 Tohoku Offshore the Pacific Coast Earthquake

Nobuyuki OGINO
Yoshihisa KITAMURA
Nagahide KANI
The Japan Society of Seismic Isolation, Shibuyaku Tokyo, Japan
Nippon Gomu Kyokaishi,(2012),85(4),138-145 General Review in Japanese

The Tohoku Offshore the Pacific Coast Earthquake occurred on March 11th 2011 as scale M: 9.0, which was with a number of aftershocks; (up to April 11th, for one month, four times >M7, forty-six times >M6, two hundred times >M5).
There are more than 3,000 buildings with seismic- isolation in Japan. The effects of seismically isolated (SI) buildings were extremely excellent during earthquakes. Displacements of SI buildings by installed tracers in Tohoku & Kanto Area were as follows;
Tohoku: 15~20 cm (Average) , 40 cm (Maximum)
Kanto: 5~8 cm (Average), 15 cm (Maximum)

Also, SI effects were confirmed from seismographs records. Real perceptions of occupants reconfirmed SI effects. Nothing fell nor moved such as furniture, household-articles in SI buildings. There is no problem in the business continuation in the offices or factories with SI.
JSSI had set up the committee for response-controlled (RC) buildings regarding the 2011 Tohoku earthquake. The committee is investigating, analyzing and reviewing the behavior of RC buildings. JSSI will confirm the effect of these RC structures, also identify problems concerning these structures, and solve them. The activities of the committee will contribute to future disaster prevention and to technical development. This paper shows the synopses of these activities.

Keywords: Seismic-Isolation, Earthquakes, Expansion Joints, Steel-Dampers, Lead-Dampers, Lead Rubber Bearings